Those joints need to be protected somehow.
Caulking siding joints.
The answer depends on the manufacturer and installation method used when the siding was first installed.
Joint flashing butt joint horizontal lap treatment june 2014 james hardie does not recommend caulking butt joints or the horizontal overlaps joint flashing 6 in.
Sometimes the old caulk in the siding joint is cracked and you need to cut the old caulk out with a razor knife.
There s no way around regular maintenance of those siding butt joints unless you want to completely remove the siding and install joint flashing.
Butt joints but not all butt joints.
Although i do not understand why they have not changed the information about caulking in the instruction manual.
25 4 mm on overlap no caulk figure 1.
Generally we do not recommend caulking butt joints on cedar siding.
While as a diyer you might be obsessing about your caulking skill truth be told that will not matter if you don t have the right caulk.
Caulking around windows doors eaves and trim edges gives added insurance that leaks will not occur.
If overused or incorrectly placed siding caulk can cause more damage to your exterior than good.
Similar to weatherstripping caulk strips are pre shaped rolls of sealant that have a peel and stick installation.
When james hardie siding products butt into wood based materials a 1 8 gap will allow for expansion and contraction of the wood based product.
Natural siding boards are designed to expand and contract.
Deterioration of the caulking in the joint has become a maintenance issue for home owners over time.
Joint flashing is recommended for all hardie lap siding now.
When deciding how to use caulk on your siding however it is generally more important to consider where you should not use it.
Caulk backer rods are lengths of foam that help fill large gaps before caulking.
It is generally not a good idea to use caulking on wood siding.
James hardie also does not recommend applying caulk to the horizontal overlap between siding planks see figure 2.
Where two pieces of siding meet.
152 4 mm wide 1 in.
These siding joints can be caulked successfully if the gap is wide enough for the caulk to get into the crack.
If the siding joint is so tight that the caulk only bridges the gap it may split again.
